Magnetic resonance imaging system, magnetic resonance imaging apparatus, cooling control apparatus, and cooling control method

Abstract

An object is to provide a backup system for cooling of a magnet with a simpler configuration. A magnetic resonance imaging system according to the present embodiment includes a first magnetic resonance imaging device, a first cooling system, a second magnetic resonance imaging device, a second cooling system, and a cooling control device. The first magnetic resonance imaging device includes a first magnet that generates a static magnetic field. The first cooling system cools the first magnet. The second magnetic resonance imaging device includes a second magnet that generates a static magnetic field. The second cooling system cools the second magnet. The cooling control device switches a cooling target between the first cooling system and the second cooling system.

Description

[0001] Cross-referencing of related applications

[0002] This application claims priority based on Japanese Patent Application No. 2021-088649, filed on May 26, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The implementation methods involve magnetic resonance imaging systems, magnetic resonance imaging devices, cooling control devices, and cooling control methods. Background Technology

[0004] Liquid helium is used as a coolant for static magnetic field magnets in many magnetic resonance imaging (MRI) devices. However, due to the rising market price of helium and the surge in demand in recent years, there is a need to reduce the use of liquid helium.

[0005] Since less refrigerant results in less total heat dissipation, a malfunction in the compressor or chilled water circulation system (also called a cooler) used to cool the static magnetic field magnets in a refrigeration unit can lead to a rapid temperature rise within minutes to hours, potentially causing quenching. Once quenching occurs, a large amount of refrigerant and prolonged refrigeration unit operation are required to cool the magnets back to a re-excitation temperature, increasing downtime and costs.

[0006] Therefore, it is also possible to prepare two compressors and coolers for the cryo-system as a backup for one MRI device, but this would require space and increase the overall price of the MRI device.

[0007] Existing technical documents

[0008] Patent Document 1: Japanese Patent Publication No. 2019-506923

[0009] Patent Document 2: Japanese Patent Publication No. 2019-520910 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] One of the technical problems to be solved by the technical solutions disclosed in this specification and accompanying drawings is to provide a backup system for cooling magnets with a simpler structure. However, the technical problems to be solved by the technical solutions disclosed in this specification and accompanying drawings are not limited to the above-mentioned technical problems. Other technical problems may also be identified as those corresponding to the effects of the various structures shown in the embodiments described below.

[0012] The magnetic resonance imaging system of this technical solution includes a first magnetic resonance imaging device, a first cooling system, a second magnetic resonance imaging device, a second cooling system, and a cooling control device. The first magnetic resonance imaging device includes a first magnet that generates a static magnetic field. The first cooling system cools the first magnet. The second magnetic resonance imaging device includes a second magnet that generates a static magnetic field. The second cooling system cools the second magnet. The cooling control device switches the cooling target between the first cooling system and the second cooling system.

[0013] Invention Effects

[0014] It can provide a backup system for cooling the magnets with a simpler structure. Attached Figure Description

[0015] Figure 1 This is a conceptual diagram of the magnetic resonance imaging system according to this embodiment.

[0016] Figure 2 This is a block diagram illustrating the magnetic resonance imaging apparatus according to this embodiment.

[0017] Figure 3 This is a block diagram showing a specific structural example of a cooling device, including the cooling system and cooling control device.

[0018] Figure 4 This is a flowchart illustrating the operation of a magnetic resonance imaging system.

[0019] Figure 5 This is the first example of a switching process that occurs when an abnormality occurs in a part of the cooling system.

[0020] Figure 6 This is the second example of a switching process that occurs when an abnormality occurs in a part of the cooling system.

[0021] Figure 7 This is the third example of a switching process that occurs when an abnormality occurs in a part of the cooling system.

[0022] Figure 8 This is a block diagram illustrating an example of different numbers of cooling systems and magnetic resonance imaging devices.

[0023] Figure 9 This diagram illustrates an example of cooling implemented using a time-sharing method.

[0024] Label Explanation

[0025] 1 MRI system

[0026] 10, 10-1, 10-2 MRI devices

[0027] 20, 20-1, 20-2 Cooling systems

[0028] 21 Cooling control device

[0029] 30 Magnet Management Unit

[0030] 101, 101-1, 101-2, 101-3 Static Magnetic Field Magnets

[0031] 103 Gradient Magnetic Field Coil

[0032] 105 Gradient Magnetic Field Power Supply

[0033] 107 examination beds

[0034] 109 Examination Bed Control Circuit

[0035] 111 Cavity

[0036] 113 Transmitting Circuit

[0037] 115 Transmitting Coil

[0038] 117 Receiving Coil

[0039] 119 Receiver Circuit

[0040] 121 Sequence Control Circuit

[0041] 123 bus

[0042] 125 interface

[0043] 127 monitor

[0044] 129 Storage devices

[0045] 131 Processing Circuit

[0046] 201, 201-1, 201-2 Coolers

[0047] 202 Cold Water Switch

[0048] Compressors 203, 203-1, and 203-2

[0049] 204 Action Gas Switch

[0050] 205, 205-1, 205-2 cold blocks

[0051] 206 Control Circuit

[0052] 301 Temperature Measurement Circuit

[0053] 302 Pressure Measurement Circuit

[0054] 1071 Top Plate

[0055] 1311 System Control Functions

[0056] 1313 Image generation function

[0057] 1315 Detection Function

[0058] 1317 Inference Function

[0059] 2061 Detection Function

[0060] 2063 Switching Function

[0061] 2065 Notification Function Detailed Implementation

[0062] In general, according to one embodiment, the magnetic resonance imaging system, magnetic resonance imaging apparatus, cooling control device, and cooling control method include the following.

[0063] The magnetic resonance imaging system of this embodiment includes a first magnetic resonance imaging device, a first cooling system, a second magnetic resonance imaging device, a second cooling system, and a cooling control device. The first magnetic resonance imaging device includes a first magnet that generates a static magnetic field. The first cooling system cools the first magnet. The second magnetic resonance imaging device includes a second magnet that generates a static magnetic field. The second cooling system cools the second magnet. The cooling control device switches the cooling target between the first cooling system and the second cooling system.

[0064] The following is a reference to the appendix. Figure 1 The magnetic resonance imaging system (hereinafter referred to as MRI system), MRI apparatus, cooling control device, and cooling control method of this embodiment will be described. In the following embodiments, it is assumed that parts with the same reference numerals perform the same operation, and repeated descriptions are omitted where appropriate.

[0065] Figure 1 This is a conceptual diagram illustrating the MRI system according to this embodiment.

[0066] like Figure 1 As shown, the MRI system 1 includes multiple MRI units 10, multiple cooling systems 20, and a cooling control device 21. Furthermore, the following description, without assigning branch numbers to units such as the MRI units 10, serves as a general description of the same structure.

[0067] In addition, Figure 1The following examples primarily illustrate two scenarios in MRI system 1: a group of MRI devices 10-1 and cooling systems 20-1, and a group of MRI devices 10-2 and cooling systems 20-2. However, this is not a limitation; there may be three or more groups of MRI devices 10 and cooling systems 20. Furthermore, the cooling systems 20 may not correspond one-to-one with the MRI devices 10. For example, there may be two or more cooling systems 20, and the number of MRI devices 10 may be less than one; for this case, please refer to [reference needed]. Figure 8 To be described later.

[0068] Each MRI device 10 generates MR images by applying a high-frequency magnetic field to the subject and collecting magnetic resonance signals (MR signals) obtained from the magnetic resonance phenomenon of protons passing through the biological body. For the MRI device 10, refer to... Figure 2 To be described later.

[0069] Each cooling system 20 is basically connected one-to-one with the MRI device 10, and cools the static magnetic field magnet inside the MRI device 10, which is the object of cooling.

[0070] The cooling control device 21 switches between the cooling control of each MRI device 10 and each cooling system 20. For example, if an abnormality occurs, such as a malfunction of one of the multiple cooling systems 20, the cooling control device 21 switches the connection to another cooling system 20 that is operating normally, and cools the static magnetic field magnet of the MRI device 10 connected to the malfunctioning cooling system 20.

[0071] Next, refer to Figure 2 The block diagram illustrates the details of the MRI device 10.

[0072] like Figure 2 As shown, the MRI device 10 includes a static magnetic field magnet 101, a magnet management unit 30, a gradient magnetic field coil 103, a gradient magnetic field power supply 105, an examination table 107, an examination table control circuit 109, a transmitting circuit 113, a transmitting coil 115, a receiving coil 117, a receiving circuit 119, a sequence control circuit 121, a bus 123, an interface 125, a display 127, a storage device 129, and a processing circuit 131. Alternatively, the MRI device 10 may also have a hollow cylindrical shimming coil between the static magnetic field magnet 101 and the gradient magnetic field coil 103.

[0073] The static magnetic field magnet 101 is a magnet formed in a hollow, generally cylindrical shape. However, the static magnetic field magnet 101 is not limited to a generally cylindrical shape and can also be configured in an open shape. The static magnetic field magnet 101 generates a uniform static magnetic field within its internal space. In this embodiment, a superconducting magnet with a superconducting coil is envisioned as the static magnetic field magnet 101.

[0074] The gradient magnetic field coil 103 is a coil formed into a hollow cylindrical shape. The gradient magnetic field coil 103 is disposed inside the static magnetic field magnet 101. The gradient magnetic field coil 103 is formed by combining three coils corresponding to the mutually orthogonal X, Y, and Z axes. It is assumed that the Z-axis direction is the same as the direction of the static magnetic field. Furthermore, it is assumed that the Y-axis direction is vertical, and the X-axis direction is perpendicular to both the Z and Y axes. The three coils of the gradient magnetic field coil 103 receive current individually from the gradient magnetic field power supply 105, generating a gradient magnetic field whose magnetic field strength varies along the X, Y, and Z axes.

[0075] The gradient magnetic fields along the X, Y, and Z axes generated by the gradient magnetic field coil 103 form, for example, gradient magnetic fields for frequency encoding (also called readout gradient magnetic fields), gradient magnetic fields for phase encoding, and gradient magnetic fields for slice selection. The gradient magnetic field for frequency encoding is used to change the frequency of the MR signal according to its spatial position. The gradient magnetic field for phase encoding is used to change the phase of the MR signal according to its spatial position. The gradient magnetic field for slice selection is used to determine the imaging cross-section.

[0076] The gradient magnetic field power supply 105 is a power supply device that supplies current to the gradient magnetic field coil 103 under the control of the sequence control circuit 121.

[0077] The examination bed 107 is a device equipped with a top plate 1071 for placing the subject P. Under the control of the examination bed control circuit 109, the top plate 1071 for placing the subject P is inserted into the cavity 111. The examination bed 107 is, for example, arranged in an examination room where an MRI device 10 is installed, with its length direction parallel to the central axis of the static magnetic field magnet 101.

[0078] The examination bed control circuit 109 is a circuit that controls the examination bed 107. By using the operator's instructions via the interface 125, the examination bed 107 is driven, thereby causing the top plate 1071 to move in the length direction and the vertical direction.

[0079] The transmitting coil 115 is an RF coil disposed inside the gradient magnetic field coil 103. The transmitting coil 115 receives RF (Radio Frequency) pulses from the transmitting circuit 113 and generates a transmitted RF wave equivalent to a high-frequency magnetic field. The transmitting coil 115 is, for example, a full-body coil. A full-body coil can also be used as a transceiver coil. A cylindrical RF shield is provided between the full-body coil and the gradient magnetic field coil 103 to magnetically separate these coils.

[0080] The transmitting circuit 113 supplies RF pulses corresponding to the Larmor frequency to the transmitting coil 115 under the control of the sequence control circuit 121.

[0081] The receiving coil 117 is an RF coil disposed inside the gradient magnetic field coil 103. The receiving coil 117 receives the MR signal emitted from the subject P by a high-frequency magnetic field. The receiving coil 117 outputs the received MR signal to the receiving circuit 119. The receiving coil 117 is, for example, a coil array having one or more coil elements, typically multiple coil elements. The receiving coil 117 is, for example, a phased array coil.

[0082] The receiving circuit 119, under the control of the sequence control circuit 121, generates a digitized MR signal as complex data based on the MR signal output from the receiving coil 117. Specifically, after applying various signal processing techniques to the MR signal output from the receiving coil 117, the receiving circuit 119 performs an analog-to-digital (A / D) conversion on the processed data. The receiving circuit 119 samples the A / D converted data. Thus, the receiving circuit 119 generates a digital MR signal (hereinafter referred to as MR data). The receiving circuit 119 outputs the generated MR data to the sequence control circuit 121.

[0083] The sequence control circuit 121 controls the gradient magnetic field power supply 105, the transmitting circuit 113, and the receiving circuit 119, etc., according to the inspection protocol output from the processing circuit 131, to perform imaging of the subject P. The inspection protocol has various pulse sequences (also called imaging sequences) corresponding to the inspection. The inspection protocol defines the magnitude of the current supplied by the gradient magnetic field power supply 105 to the gradient magnetic field coil 103, the timing of the current supplied by the gradient magnetic field power supply 105 to the gradient magnetic field coil 103, the magnitude of the RF pulse supplied by the transmitting circuit 113 to the transmitting coil 115, the timing of the RF pulse supplied by the transmitting circuit 113 to the transmitting coil 115, and the timing of the MR signal received by the receiving coil 117, etc.

[0084] Bus 123 is a transmission path that enables data to be transmitted between interface 125, display 127, storage device 129, and processing circuit 131. Various biosignal detectors, external storage devices, and various modalities can also be appropriately connected to bus 123 via networks or the like. For example, an electrocardiogram (ECG) not shown can be connected to the bus as a biosignal detector.

[0085] Interface 125 has circuitry for receiving various instructions and information inputs from the operator. Interface 125 may include circuitry for, for example, a pointing device such as a mouse or an input device such as a keyboard. However, the circuitry of interface 125 is not limited to circuitry for physical operating components such as a mouse or keyboard. For example, interface 125 may also include signal processing circuitry that receives electrical signals corresponding to input operations from an external input device separately located from the MRI apparatus 10 and outputs the received electrical signals to various circuits.

[0086] Under the control of the system control function 1311 in the processing circuit 131, the display 127 displays various magnetic resonance images (MR images), imaging and image processing related information generated by the image generation function 1313. The display 127 is, for example, a CRT display, liquid crystal display, organic EL display, LED display, plasma display, or any other display, monitor, etc. known in the art.

[0087] Storage device 129 stores MR data filled in the k-space by image generation function 1313, image data generated by image generation function 1313, etc. Storage device 129 stores various inspection protocols, including imaging conditions specifying multiple imaging parameters of the inspection protocols. Storage device 129 stores programs corresponding to various functions executed by processing circuit 131. Storage device 129 can be, for example, a semiconductor memory element such as RAM (Random Access Memory), flash memory, a hard disk drive, a solid-state drive, an optical disc, etc. Furthermore, storage device 129 can also be a CD-ROM drive or DVD drive, a drive device for reading and writing various information between itself and removable storage media such as flash memory, etc.

[0088] The magnet management unit 30 includes a temperature measurement circuit 301 and a pressure measurement circuit 302.

[0089] The temperature measurement circuit 301 uses, for example, a resistive temperature sensor to measure the temperature of one or more superconducting coils that form the static magnetic field magnet 101.

[0090] The pressure measurement circuit 302 uses, for example, a pressure sensor to measure the pressure of the operating gas used to activate the cooling system 20 that cools the static magnetic field magnet 101 described later.

[0091] The processing circuit 131, as a hardware resource, includes a processor (not shown), a memory such as ROM (Read-Only Memory) and RAM, and comprehensively controls the MRI device 10. The processing circuit 131 includes system control function 1311, image generation function 1313, detection function 1315, and inference function 1317.

[0092] The various functions of the processing circuit 131 are stored in the storage device 129 in the form of programs executable by a computer. The processing circuit 131 is a processor that implements the functions corresponding to each program by reading them from the storage device 129 and executing them. In other words, the processing circuit 131, after reading each program, has the following state: Figure 2 The processing circuit 131 represents multiple functions, etc.

[0093] In addition, Figure 2 The description assumes that these various functions are implemented by a single processing circuit 131, but multiple independent processors can also be combined to form the processing circuit 131, with each processor executing a program to implement the functions. In other words, either the above-mentioned functions can be configured as programs and executed by a single processing circuit, or specific functions can be installed in dedicated independent program execution circuits.

[0094] Additionally, the term "processor" as used in the above description refers to circuits such as CPU (Central Processing Unit), GPU (Graphics Processing Unit), or Application-Specific Integrated Circuit (ASIC), programmable logic device (e.g., Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)).

[0095] The processor performs various functions by reading and executing the program stored in the storage device 129. Alternatively, instead of storing the program in the storage device 129, the program can be directly embedded into the processor's circuitry. In this case, the processor performs the functions by reading and executing the program embedded in the circuitry. Furthermore, the examination bed control circuit 109, the transmitting circuit 113, the receiving circuit 119, the sequence control circuit 121, etc., are also composed of the electronic circuitry of the processor, etc., as described above.

[0096] Processing circuit 131 controls MRI device 10 via system control function 1311. Specifically, processing circuit 131 reads the system control program stored in storage device 129 and expands it into memory, controlling each circuit of MRI device 10 according to the expanded system control program. For example, processing circuit 131 reads the examination protocol from storage device 129 based on the imaging conditions input by the operator via interface 125 through system control function 1311. Alternatively, processing circuit 131 can also generate an examination protocol based on the imaging conditions. Processing circuit 131 sends the examination protocol to sequence control circuit 121 to control imaging of subject P.

[0097] The processing circuit 131 is controlled by the system control function 1311 to apply excitation pulses and a gradient magnetic field according to the excitation pulse sequence. After executing the excitation pulse sequence, the processing circuit 131, through the system control function 1311, collects MR signals from the subject P according to various data collection pulse sequences, i.e., data collection sequences, and generates MR data.

[0098] Processing circuit 131 fills MR data along the readout direction of k-space according to the strength of the readout gradient magnetic field using image generation function 1313. Processing circuit 131 generates an MR image by performing a Fourier transform on the MR data filled in k-space. For example, processing circuit 131 can generate an absolute value (Magnitude) image from complex MR data. Furthermore, processing circuit 131 can generate a phase image using the real and imaginary parts of the complex MR data. Processing circuit 131 outputs the MR image, including the absolute value image and the phase image, to display 127 or storage device 129.

[0099] The processing circuit 131 detects whether an abnormality has occurred in the cooling system 20 of the static magnetic field magnet 101 by means of the detection function 1315, based on information such as temperature and pressure related from the magnet management unit 30.

[0100] The processing circuit 131 infers, through the inference function 1317, the period during which imaging corresponding to the imaging conditions can continue when the cooling system 20 does not operate relative to the static magnetic field magnet 101, in other words, the period during which the temperature of the static magnetic field magnet 101 is above the threshold.

[0101] Next, refer to Figure 3 A specific structural example of a cooling device, including a cooling system 20 and a cooling control device 21, will be described.

[0102] Figure 3The cooling device shown includes coolers 201-1 and 201-2, a cold water switch 202, compressors 203-1 and 203-2, an operating gas switch 204, a cold head 205-1 and 205-2, and a control circuit 206.

[0103] Coolers 201-1 and 201-2, compressors 203-1 and 203-2, and cold heads 205-1 and 205-2 are part of the cooling system 20 for the MRI apparatus 10. Additionally, the cooling system 20, although not shown, includes a supply pipe, a discharge pipe, a vent valve, a suction valve, and a buffer tank. The chilled water switch 202, the operating gas switch 204, and the control circuit 206 are part of the cooling control device 21.

[0104] exist Figure 3 In this design, we envision two MRI units 10-1 and 10-2 arranged side-by-side in each examination chamber, with cooling devices connected to the static magnetic field magnets 101-1 and 101-2 of both MRI units 10-1 and 10-2, respectively. We also envision a configuration where the portion of the cooling device connected to the static magnetic field magnet 101, excluding the cooling head 205, is located outside the examination chamber. Alternatively, if the structure would not affect imaging even if placed in an examination chamber subject to noise countermeasures and non-magnetic treatment, the cooling device could be placed inside the examination chamber. Furthermore, for ease of explanation, illustrations of elements other than the static magnetic field magnet 101 are omitted from the diagrams of each MRI unit 10.

[0105] Here, the specific structure of the static magnetic field magnet 101 will be explained.

[0106] The static magnetic field magnet 101 is a superconducting magnet that generates a static magnetic field by supplying current to the superconducting coil in a superconducting state. As an example, the superconducting coil, along with liquid helium as a refrigerant to maintain a sufficiently low temperature within the container to preserve the superconducting state, is housed in a generally cylindrical cooling container (not shown). The cooling container is housed within the cylindrical wall of a vacuum container (not shown). Inside the cooling container, liquid helium and helium vaporized from liquid helium are in equilibrium.

[0107] Inside the cooling container, there is a heater (not shown). The heater heats the helium inside the cooling container, causing it to vaporize, and regulates the pressure inside the cooling container. This pressure regulation is, for example, to prevent unwanted air from flowing into the cooling container. If the helium inside the cooling container is overcooled, the proportion of liquid helium in the cooling container increases, and the pressure inside the cooling container drops. If the pressure inside the cooling container drops and becomes negative, air will flow into the cooling container. The heater is controlled to keep the pressure inside the cooling container within a preset range.

[0108] exist Figure 3 In subsequent examples, we envision a scenario where the static magnetic field magnet 101-1 of MRI device 10-1 contains a larger amount of refrigerant than the static magnetic field magnet 101-2 of MRI device 10-2, i.e., a larger amount of liquid helium in the cooling container. However, this is not a limitation; the amount of liquid helium in static magnetic field magnets 101-1 and 101-2 can also be approximately the same.

[0109] During normal operation, for the static magnetic field magnet 101-1, the cooler 201-1, compressor 203-1, and cold head 205-1 operate as cooling system 20-1; for the static magnetic field magnet 101-2, the cooler 201-2, compressor 203-2, and cold head 205-2 operate as cooling system 20-2. That is, during normal operation, each magnet is cooled by an independent cooling system.

[0110] Cooler 201 is connected to compressor 203 via chilled water switch 202, and dissipates heat from compressor 203 into the atmosphere by circulating cooling water. In other words, cooler 201 is a cooling water circulator that dissipates heat from compressor 203.

[0111] The chilled water switch 202 switches the flow path of cooling water between coolers 201-1 and 201-2 and compressors 203-1 and 203-2 according to the instruction from the control circuit 206. For example, the flow path can be switched simply by controlling a valve. The flow path (path) switching control by the valve can be done by the usual method, and specific details are omitted.

[0112] Compressor 203 is connected to cold head 205 via a supply pipe and a discharge pipe. For example, a refrigerant such as helium is compressed by a motor, resulting in a high-pressure refrigerant gas, which is then supplied to cold head 205 via the supply pipe. The compressor 203 recovers the refrigerant gas that expands inside cold head 205 via the discharge pipe. Furthermore, compressor 203 is connected to a buffer tank filled with refrigerant gas via a vent valve and a suction valve. The buffer tank is filled with refrigerant gas. Compressor 203 discharges the refrigerant gas into the buffer tank via the vent valve. Compressor 203 draws in the refrigerant gas filled in the buffer tank via the suction valve.

[0113] The operating gas switcher 204 switches the flow path of the operating gas between compressors 203-1 and 203-2 and cold heads 205-1 and 205-2 according to the instruction from the control circuit 206. For example, the flow path can be switched simply by controlling the gas valve. The flow path (path) switching control by the valve can be done by the usual method, and specific explanation is omitted.

[0114] The cold head 205 is the end of the cooling system 20 that is connected to the static magnetic field magnet 101. It expands the high-pressure operating gas supplied via the supply pipe, cooling the refrigerant contained in the cooling container. The cold head 205 cools the refrigerant contained in the cooling container to a temperature below its boiling point. If the cooling container is cooled to a certain extent, the helium gas inside the cooling container is re-condensed into liquid helium. Furthermore, in... Figure 1 The example shown is a case where one cold head 205 is set for the magnet, but the cold head 205 is not limited to one, and there can be multiple cold heads.

[0115] The control circuit 206 includes a detection function 2061, a switching function 2063, and a notification function 2065, which controls the operation of the cooling system 20 and the cooling control device 21. The control circuit 206 can be implemented by a processor such as a CPU, GPU, or ASIC.

[0116] The control circuit 206 detects abnormalities in the cooling system 20 through the detection function 2061. For example, an abnormality can be detected if the remaining refrigerant level of the cooling magnet, the operating status of the compressor, the pressure of the moving gas, the operating status of the cooler, or the flow rate of the cooling water are outside the normal range.

[0117] When the control circuit 206 detects an abnormality in the cooling system 20, it controls at least one of the cold water switcher 202 and the operating gas switcher 204 according to the abnormal state through the switching function 2063, thereby switching the flow path of the cooling water or the operating gas.

[0118] When an anomaly is detected, the control circuit 206 notifies the outside of the occurrence of the anomaly via the notification function 2065. Furthermore, the control circuit 206 also notifies the outside of a switching signal indicating that the flow path of the cooling system 20 will be switched during operation via the notification function 2065.

[0119] Additionally, a vent valve and a suction valve are located in the pipe connecting the compressor 203 to the buffer tank. The vent valve discharges the refrigerant gas inside the compressor 203 into the buffer tank. By discharging the refrigerant gas from the compressor 203, the pressure of the refrigerant gas supplied from the compressor 203 to the cold head 205 decreases. The suction valve, for example, supplies the refrigerant gas filled in the buffer tank to the compressor 203 according to an instruction from the control circuit 206. By supplying refrigerant gas to the compressor 203, the pressure of the refrigerant gas supplied from the compressor 203 to the cold head 205 increases.

[0120] Next, refer to Figure 4 The flowchart describes the switching operation of the MRI system 1 according to this embodiment.

[0121] In step S401, an anomaly in the cooling system 20 is detected. Besides the method described above using the detection function 2061 of the control circuit 206, the method for detecting an anomaly may also involve the cooler 201 or compressor 203 sending an error signal to the control circuit 206 when the cooler 201 or compressor 203 itself can generate an error signal. The control circuit 206 then receives this error signal to detect an anomaly in the cooling system 20. Furthermore, if the control circuit 206 regularly or periodically obtains a status signal indicating normal operation from the cooling system 20, it may also determine that the cooling system 20 is abnormal if this signal cannot be obtained through the detection function 2061. Alternatively, the anomaly detection process may be performed not in the control circuit 206, but in the processing circuit 131 of each MRI device 10.

[0122] In step S402, it is specifically determined at which part the abnormality occurred. Here, it is determined whether the abnormality occurred in the compressor 203 or the cooler 201. That is, in the control circuit 206 of the cooling control device 21 or in each MRI device 10, it is determined that the abnormality occurred in the compressor 203 if an error signal is received from the compressor 203 or if no status signal is received, and it is determined that the abnormality occurred in the cooler 201 if an error signal is received from the cooler 201 or if no status signal is received. If the abnormality is in the compressor 203, proceed to step S403; if the abnormality is in the cooler 201, proceed to step S405.

[0123] In step S403, the switching function 2063 of the control circuit 206 controls the action gas switcher 204 to switch the flow path of the action gas for the static magnetic field magnet 101 of the MRI device 10 that is connected to the compressor 203 that malfunctioned when it is normal, so as to supply the action gas from the normal compressor 203 to the cold head 205.

[0124] In step S404, for example, the notification function 2065 of the control circuit 206 sends an inefficient operation signal, which indicates an inefficient (fallback) operation instruction to perform restricted imaging, to each MRI device 10.

[0125] In step S405, the switching function 2063 of the control circuit 206 controls the cold water switch 202 to switch the flow path of the cooling water to supply cooling water from the normal cooler 201 to the compressor 203 connected to the malfunctioning cooler 201 when it is in normal operation. Then, proceeding to step S404, an inefficient operation signal is sent to each MRI device 10 respectively.

[0126] Alternatively, in the event of an abnormality in the cooling system 20 and the detection of a faulty component, the notification function 2065 of the control circuit 206 can send a switching signal to the outside, including the occurrence of the abnormality, the location of the abnormality, the inefficient operation being implemented, and which cooling system flow path is being switched to operate. For example, by automatically notifying medical practitioners and service personnel of the switching signal from the cooling control device 21, the time until repairs are initiated can be shortened, which can help reduce downtime and costs during periods when the MRI device 10 cannot be used.

[0127] Next, refer to Figure 5 The first example of a switching process in the event of an abnormality occurring in a part of the cooling system 20 will be described.

[0128] Figure 5 envisioned as Figure 3 The following describes a scenario where the compressor 203-2 of the cooling system 20 malfunctions. In this case, it is assumed that the control circuit 206 detects an anomaly based on the status signal of the compressor 203-2. Upon instruction from the control circuit 206, the operating gas switch 204 switches the flow path to supply the operating gas from the compressor 203-1 to the cold head 205-2 connected to the static magnetic field magnet 101-2. Through this switching, the static magnetic field magnet 101-1 is not cooled by the cooling system 20. Therefore, based on the control actions of the MRI device 10-1, there is a possibility that the abnormal cooling of the static magnetic field magnet 101 is detected by a pressure sensor that detects the pressure of the operating gas supplied to the cold head 205-1, and the process is stopped from proceeding to the next imaging session as an error.

[0129] For the MRI device 10 that has thus entered a stopped state, it can remain in its stopped state or continue imaging under specified imaging conditions. For example, before or approximately simultaneously with the switching instruction sent from the control circuit 206 to the action gas switcher 204, an inefficient operation signal can be sent from the control circuit 206 to the sequence control circuit 121 of the MRI device 10. Upon receiving the inefficient operation instruction, the MRI device 10 continues imaging under specified imaging conditions. These specified imaging conditions refer to, for example, situations where normal imaging can be performed for one day, but thereafter the number of imaging sessions or the number of imaging sessions per day is limited, or imaging sequences involving frequent magnetic field switching that would increase coil heat generation, such as those that cannot perform EPI (Echo Planar Imaging), are included. As described above, imaging conditions can include the number of imaging sessions, the number of imaging sessions, the type of imaging sequence, etc., but are not limited to these. Any condition that minimizes the temperature rise of the static magnetic field magnet 101 or minimizes the rate of temperature rise is acceptable.

[0130] Furthermore, in the MRI apparatus 10-1, it is also possible to estimate how long imaging can continue or the period during which imaging can be performed when the static magnetic field magnet 101-1 is not cooled. For example, by using the estimation function 1317 of the processing circuit 131 of the MRI apparatus 10-1, based on the current temperature of the static magnetic field magnet 101-1 from the magnet management unit 30 and the estimated temperature rise of the static magnetic field magnet 101-1 under the condition of performing an imaging sequence according to future inspection plans, it is estimated that the period during which the temperature of the static magnetic field magnet 101 will reach a threshold or higher can be estimated. Thus, it is possible to estimate how long imaging can continue, so that maintenance plans for the cooling system 20 can be easily set while minimizing downtime. In addition, the control circuit 206 of the cooling control device 21 can also obtain temperature-related information of the static magnetic field magnet 101-1 of the MRI apparatus 10-1 to estimate the aforementioned period during which imaging can be performed.

[0131] The reason why recording can continue even when the cooling of the static magnetic field magnet 101 stops is that, with a large amount of refrigerant (liquid helium) in the static magnetic field magnet 101, even if the cooling system 20 stops, the internal temperature of the static magnetic field magnet will not immediately rise to the temperature that breaks the superconductivity state through heat dissipation caused by the evaporation of liquid helium. Therefore, recording can continue for the specified period.

[0132] Furthermore, if the compressor 203-1 is set to stop operating if the pressure of the operating gas changes by more than a threshold, the operating gas switch 204 may cause pressure changes during the switching process from cold head 205-1 to cold head 205-2, potentially causing the compressor 203-1 to stop. In this case, an inefficient operation signal indicating that a switching process has been performed is sent to both MRI unit 10-1 and MRI unit 10-2. Therefore, the compressor 203-1 can be restarted simply by sending a restart-urging reset signal from MRI unit 10 to the compressor 203-1. Alternatively, the compressor 203-1 can be restarted via the control circuit 206. In this case, the compressor 203-1 can be restarted via the control circuit 206 for both MRI unit 10-1 and MRI unit 10-2.

[0133] Alternatively, an allowable range can be set for the compressor 203 related to the pressure change anticipated during the switching process. Therefore, even if a switching process is performed, the compressor 203 can continue operating without stopping because the pressure change is pre-planned.

[0134] Next, refer to Figure 6 The second example of switching procedures in the event of an anomaly occurring in a part of the cooling system 20 will be described.

[0135] Figure 6and Figure 5 In contrast, we envisioned a scenario where the failure was not due to compressor 203-2 but rather to cooler 201-2.

[0136] For example, through the detection function 2061, the control circuit 206 detects that the cooler 201-2 is abnormal based on the status signal of the cooler 201-2.

[0137] As instructed by the control circuit 206 based on the switching function 2063, the chilled water switcher 202 switches the flow path to supply cooling water from the cooler 201-1 to the compressor 203-2. Through this switching, according to the control design of the MRI device 10, there are cases where the compressor 203-1 stops flowing, and subsequently, the cooling of the static magnetic field magnet 101-1 stops when the compressor 203-1 stops. As a result, with... Figure 5 Similarly, there are cases where the function is to stop proceeding to the next shot as an error.

[0138] In such a case, an inefficient operation signal may also be sent to the sequence control circuit 121 of the MRI device 10-1 before or approximately simultaneously with the switching instruction sent from the control circuit 206 to the cold water switcher 202.

[0139] Furthermore, regarding compressor 203-2 and cooler 201-1, due to the fluctuation in cooling water pressure during the switching operation, it is conceivable that the operation of compressor 203-2 and cooler 201-1 will cease. In this situation, it is also related to... Figure 5 Similarly, all that is needed is for MRI device 10-1 to cooler 201-1 and MRI device 10-2 to compressor 203-2 to send a reset signal for restart.

[0140] Next, refer to Figure 7 The third example of switching procedures in the event of an anomaly occurring in a part of the cooling system will be described.

[0141] Figure 7 and Figure 6 This also indicates an abnormality occurred in cooler 201-2, but... Figure 6 Unlike the switching mechanism, the chilled water switcher 202 does not switch the flow path of the cooling water in the cooler 201-1 to the compressor 203-2 side. Instead, it maintains the original flow path of the cooler 201-1 connected to the compressor 203-1, as during normal operation. However, the operating gas switcher 204 switches the flow path of the operating gas in the compressor 203-1 to the cold head 205-2 side. Therefore, in the event of an abnormality in the cooler 201, either the chilled water switcher 202 or the operating gas switcher 204 can be switched.

[0142] Next, refer to Figure 8 An example is given for MRI systems 1 with more than one MRI unit having a cooling system 20.

[0143] When there are three or more units in the group of MRI device 10 and cooling system 20, it is also related to... Figures 5 to 7 The flow path of the cooling system 20 can also be switched as shown. That is, the static magnetic field magnet 101 can be cooled by switching the flow path of the cooling water or the working gas using another cooling system 20 that is operating normally, except for the cooler 201 or compressor 203 that has malfunctioned.

[0144] Alternatively, the cooling system 20 may be fewer in number than the MRI device 10. In this case, it is sufficient to simply switch the flow path sequentially during normal operation to cool the static magnetic field magnet 101. Figure 8 In the example, it represents a configuration with two coolers 201 (cooler 201-1, cooler 201-2), three compressors (compressor 203-1, compressor 203-2, compressor 203-3), and three static magnetic field magnets 101 (static magnetic field magnet 101-1, static magnetic field magnet 101-2, static magnetic field magnet 101-3). The control circuit 206 only needs to control the time-sharing of coolers 201-1 and 201-2 by the chilled water switcher 202, ensuring that cooling water circulates equally to each compressor 203, thereby cooling each static magnetic field magnet 101.

[0145] In addition, in the above Figures 5 to 7 Similarly, in the same case, each static magnetic field magnet 101 can be cooled in a time-sharing manner. Figure 9 The diagram illustrates an example of switching the flow path of the cooling system 20 in a time-sharing manner.

[0146] Figure 9 (a) is a cooling pattern in which static magnetic field magnets 101-1 and 101-2 are cooled for equal time in the event of an anomaly in the cooling system 20. Furthermore, Figure 9 (b) is a cooling pattern in which static magnetic field magnets 101-1 and 101-2 are cooled with unequal cooling times. For example, in the case of two magnets of the same type, since the time until the static magnetic field magnets 101-1 and 101-2 are quenched depends roughly on the remaining amount of refrigerant, the cooling time can be allocated according to the remaining amount of refrigerant.

[0147] Furthermore, since the sizes of the magnets in static magnetic field magnets 101-1 and 101-2 are different, the amount of refrigerant required for cooling is also different. Therefore, the cooling time can be allocated in a time-sharing manner by calculating the estimated time to quenching based on the magnets, and by making the estimated time to quenching shorter so that the cooling time is longer.

[0148] For example, the flow path of the cooling system 20 can be switched in a time-sharing manner, so that the less refrigerant the static magnetic field magnet 101 provides, the longer the cooling time. Figure 9 In case (b), since it is assumed that the static magnetic field magnet 101-1 has a greater cooling dose than the static magnetic field magnet 101-2, the cooling time can be allocated in such a way that the cooling time for the static magnetic field magnet 101-1 is shorter and the cooling time for the static magnetic field magnet 101-2 is longer. In this way, even if an anomaly occurs in the cooling system, cooling control can be performed to ensure that imaging can continue as much as possible in the overall multiple MRI devices 10.

[0149] Furthermore, in the above example, it is envisioned that the cooling control device 21 completely switches the flow path through the water cooler switch 202 and the operating gas switch 204, but it is not limited to this. A single cooling system 20 can also control the flow path to cool the multiple static magnetic field magnets 101 separately. In other words, the water cooler switch 202 can distribute cooling water to each path, and the operating gas switch 204 can distribute operating gas to each path. For example, the valve constituting the water cooler switch 202 can be configured to create a flow path that allows cooling water to circulate from the cooler 201-1 to the compressor 203-1 and the compressor 203-2 respectively.

[0150] According to the embodiment described above, by providing a cooling control device that includes a chilled water switcher, an operating gas switcher, and a control circuit for controlling these switchers, even if an abnormality occurs in the cooling system, the path of another normally operating cooling system can be switched to cool the MRI device. For example, by continuing imaging for several days in an MRI device with a higher cooling dose, and switching the connection of the cooling system's flow path to cool the static magnetic field magnet in an MRI device with a lower cooling dose, imaging can continue.

[0151] As a result, it is possible to continue imaging as much as possible while avoiding downtime-related factors such as quenching of MRI devices with low cooling doses, thus eliminating or shortening downtime that would otherwise prevent imaging from continuing. Furthermore, since cooling continues within the MRI device with low cooling doses, sufficient time for repairs can be ensured.

[0152] According to at least one embodiment described above, a backup system for cooling the magnet can be provided with a simpler structure.

[0153] Several embodiments of the present invention have been described, but these embodiments are merely illustrative and not intended to limit the scope of the invention. These embodiments can be implemented in a wide variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope or spirit of the invention, and are included in the scope of the invention as described in the claims and its equivalents.

[0154] Regarding the above-described embodiments, as a technical solution and selective feature of the invention, the following appendix is ​​disclosed.

[0155] (Postscript 1)

[0156] A magnetic resonance imaging system includes: a first magnetic resonance imaging device including a first magnet that generates a static magnetic field; a first cooling system for cooling the first magnet; a second magnetic resonance imaging device including a second magnet that generates a static magnetic field; a second cooling system for cooling the second magnet; and a cooling control device for switching the cooling target of the first cooling system and the second cooling system.

[0157] (Postscript 2)

[0158] The first cooling system may also include: a first compressor for controlling the compression and expansion of the operating gas used to cool the first magnet; and a first cooler for circulating cooling water to dissipate heat from the first compressor. The second cooling system may also include: a second compressor for controlling the compression and expansion of the operating gas used to cool the second magnet; and a second cooler for circulating cooling water to dissipate heat from the second compressor.

[0159] (Note 3)

[0160] The cooling control device may also include: an operating gas switching unit capable of switching the flow path of the operating gas between the first compressor and the second compressor and the first magnet and the second magnet; and a cooling water switching unit capable of switching the flow path of the cooling water between the first cooler and the second cooler and the first compressor and the second compressor.

[0161] (Note 4)

[0162] The aforementioned operating gas switching unit may also be configured to, in the event of an abnormality in the first compressor, switch the flow path of the operating gas of the second compressor to cool the first magnet; and in the event of an abnormality in the second compressor, switch the flow path of the operating gas of the first compressor to cool the second magnet.

[0163] (Note 5)

[0164] The aforementioned cold water switching unit may also be configured to switch the flow path of the cooling water in the second cooler to the first compressor in the event of an abnormality in the first cooler; and to switch the flow path of the cooling water in the first cooler to the second compressor in the event of an abnormality in the second cooler.

[0165] (Note 6)

[0166] The aforementioned operating gas switching unit may also be configured to, in the event of an abnormality in the first cooler, switch the flow path of the operating gas of the second compressor to cool the first magnet; and in the event of an abnormality in the second cooler, switch the flow path of the operating gas of the first compressor to cool the second magnet.

[0167] (Note 7)

[0168] Alternatively, the cooling control device may generate an inefficient operating signal for magnetic resonance imaging devices that are not connected to a cooling system, which would allow imaging to continue under specified imaging conditions; upon receiving the inefficient operating signal, either the first or second magnetic resonance imaging device may continue imaging according to the imaging conditions.

[0169] (Postscript 8)

[0170] Alternatively, the aforementioned cooling control device may generate an inefficient operating signal for magnetic resonance imaging devices that are not connected to a cooling system, which would allow imaging to continue under specified imaging conditions; upon receiving the aforementioned inefficient operating signal, the first or second magnetic resonance imaging device may infer the period during which imaging can be performed based on the aforementioned imaging conditions.

[0171] (Note 9)

[0172] The aforementioned video recording conditions may also include at least one of the number of times video is recorded and the type of video sequence.

[0173] (Postscript 10)

[0174] The aforementioned magnetic resonance imaging system may also include: a detection unit for detecting abnormalities in the first cooling system and the second cooling system; and a notification unit for notifying an external switching signal indicating that the flow path of the first cooling system or the second cooling system will be switched when the detection unit detects an abnormality.

[0175] (Postscript 11)

[0176] The cooling control device can also use the normally operating cooling system to cool the first magnet and the second magnet in a time-sharing manner if one of the first cooling system and the second cooling system malfunctions.

[0177] (Postscript 12)

[0178] The first cooling dose held by the first magnet can also be greater than the second cooling dose held by the second magnet.

[0179] (Postscript 13)

[0180] The cooling control device described above can also perform cooling in a time-sharing manner, such that the cooling time of the second magnet is longer than that of the first magnet.

[0181] (Postscript 14)

[0182] A magnetic resonance imaging system includes: a plurality of magnetic resonance imaging devices, each including a magnet that generates a static magnetic field; a plurality of cooling systems for cooling the magnets, the number of which is less than or equal to the number of the plurality of magnetic resonance imaging devices; and a cooling control device for switching the cooling target between the plurality of cooling systems and the plurality of magnetic resonance imaging devices.

[0183] (Postscript 15)

[0184] A control method relates to a control method for multiple magnetic resonance imaging devices and multiple cooling systems, wherein each of the multiple magnetic resonance imaging devices includes a magnet that generates a static magnetic field, the multiple cooling systems cool the magnet, and the number of the multiple cooling systems is less than the number of the multiple magnetic resonance imaging devices. In the event of an anomaly in a part of the multiple cooling systems, the cooling target is switched by switching the connection of the flow path between the normally operating cooling system and the multiple magnetic resonance imaging devices.

[0185] (Postscript 16)

[0186] The cooling control device described above can also perform cooling in a time-division manner based on the amount of cooling agent in the first magnet and the second magnet and the estimated time to quench, in a manner where the cooling time is longer when the amount of cooling agent is smaller and the cooling time is longer when the estimated time to quench is shorter.

[0187] (Postscript 17)

[0188] The first cooling dose held by the first magnet can also be approximately the same as the second cooling dose held by the second magnet.

[0189] (Postscript 18)

[0190] The cooling control device described above can also control the flow path by cooling both the first magnet and the second magnet by a single cooling system.

[0191] (Postscript 19)

[0192] A magnetic resonance imaging (MRI) device includes: a first magnet that generates a static magnetic field; a first cooling system that cools the first magnet; and a cooling switching unit that switches between connecting the first cooling system to a second magnet in another MRI device and cooling the second magnet through the first cooling system.

[0193] (Postscript 20)

[0194] A magnetic resonance imaging (MRI) device includes: a first magnet that generates a static magnetic field; a first cooling system that cools the first magnet; and a cooling switching unit that connects to a second cooling system for cooling a second magnet in another MRI device and switches the cooling of the first magnet via the second cooling system.

[0195] (Postscript 21)

[0196] A cooling control device performs cooling control between multiple magnetic resonance imaging (MRI) devices and multiple cooling systems, wherein each of the MRI devices includes a magnet that generates a static magnetic field, the multiple cooling systems cool the magnet, and the number of the multiple cooling systems is less than or equal to the number of the MRI devices. In the event of an anomaly in one of the multiple cooling systems, the cooling target is switched by switching the connection of the flow path between the normally operating cooling system and the MRI devices.

Claims

1. A magnetic resonance imaging system, wherein, have: The first magnetic resonance imaging device includes a first magnet that generates a static magnetic field; The first cooling system cools the first magnet mentioned above; The second magnetic resonance imaging device includes a second magnet that generates a static magnetic field; The second cooling system cools the second magnet mentioned above; as well as The cooling control device switches the cooling target of the first cooling system and the second cooling system. The aforementioned cooling control device generates an inefficient operating signal for magnetic resonance imaging devices without a connected cooling system, which allows imaging to continue under specified imaging conditions. Upon receiving the aforementioned inefficient operation signal, either the first magnetic resonance imaging device or the second magnetic resonance imaging device continues imaging according to the aforementioned imaging conditions. Upon receiving the aforementioned inefficient operating signal, the first or second magnetic resonance imaging device infers the period during which imaging can be performed based on the aforementioned imaging conditions.

2. The magnetic resonance imaging system as described in claim 1, wherein, The aforementioned first cooling system includes: The first compressor controls the compression and expansion of the working gas used to cool the first magnet; and The first cooler uses a cooling water circulation system to dissipate heat from the aforementioned first compressor. The aforementioned second cooling system includes: The second compressor controls the compression and expansion of the working gas used to cool the second magnet; and The second cooler uses a cooling water circulation system to dissipate heat from the aforementioned second compressor.

3. The magnetic resonance imaging system as described in claim 2, wherein, The aforementioned cooling control device includes: The operating gas switching unit is capable of switching the flow path of the operating gas between the first compressor and the second compressor and the first magnet and the second magnet; and The cold water switching unit is capable of switching the flow path of the cooling water between the first cooler and the second cooler and the first compressor and the second compressor.

4. The magnetic resonance imaging system as described in claim 3, wherein, In the event of an malfunction in the first compressor, the operating gas switching unit switches the flow path of the operating gas in the second compressor to cool the first magnet. In the event of an abnormality in the second compressor, the operating gas switching unit switches the flow path of the operating gas from the first compressor to cool the second magnet.

5. The magnetic resonance imaging system as described in claim 3, wherein, In the event of an malfunction in the first cooler, the cooling water switching unit switches the flow path of the cooling water in the second cooler to connect with the first compressor. In the event of an abnormality in the second cooler, the cold water switching unit switches the flow path of the cooling water in the first cooler to connect with the second compressor.

6. The magnetic resonance imaging system as described in claim 3, wherein, In the event of an malfunction in the first cooler, the operating gas switching unit switches the flow path of the operating gas from the second compressor to cool the first magnet. In the event of an abnormality in the second cooler, the operating gas switching unit switches the flow path of the operating gas from the first compressor to cool the second magnet.

7. The magnetic resonance imaging system as claimed in claim 1, wherein, The aforementioned video recording conditions include at least one of the number of times video is recorded and the type of video sequence.

8. The magnetic resonance imaging system as claimed in claim 1, wherein, It also has: The testing department inspects the first and second cooling systems for any abnormalities. The notification department, in the event of an abnormality detected by the aforementioned detection department, notifies an external switching signal, which indicates that the flow path of the first cooling system or the second cooling system will be switched and put into operation.

9. The magnetic resonance imaging system as claimed in claim 1, wherein, In the event of an abnormality in either the first cooling system or the second cooling system, the cooling control device uses the normally functioning cooling system to cool the first magnet and the second magnet in a time-sharing manner.

10. The magnetic resonance imaging system of claim 1, wherein, The first cooling dose held by the first magnet is greater than the second cooling dose held by the second magnet, or the estimated time for the first magnet to reach quenching is longer than the estimated time for the second magnet to reach quenching.

11. The magnetic resonance imaging system of claim 10, wherein, The cooling control device cools the magnet in a time-sharing manner, with the cooling time of the second magnet being longer than that of the first magnet.

Images